Direct-line circuit and switching mechanism for telephone systems.



No. 784,292. PATENTED MAR. 7, 1905. A. K.'ANDRIANO & H. HERBSTRITT. DIR-EGT LINE CIRCUITS AND SWITCHING MECHANISM FOR TELEPHONE SYSTEMS APPLIOATION FILED NOV. 21, 1903. RENEWED JULY 11. 1904.

3 SHEETS-SHEET 1.

'PATENTED MAR. '7, 1905. A. K. ANDRIANO & H. HERBSTRITT. DIRECT LINE CIRCUITS AND SWITCHING MECHANISM FOR TELEPHONE- SYSTEMS. APPLICATION FILED NOV. 21, 1903. RENEWED JULY 11. 1904.

3 SHEETS-SHEET 2.

5a is @lttu No. 784,292. PATENTED MAR. 7,1905.

A. K. ANDRIANO 61: H. HERBSTRITT. DIRECT LINE CIRCUITS AND SWITCHING MECHANISM FOR TELEPHON SYSTEMS. APPLICATION FILED NOV. 21, 1903. RENEWED JULY 11. 1904.

3 SHEETS-SHEET 3.

UNITED STATES Patented March 7, 1905.

PATENT OFFICE.

ALBERT K. ANDRIANO, ,OF SAN FRANCISCO, CALIFORNIA, AND HERMANN HERBSTRITT, OF NEW' YORK, N. Y.. ASSIGNORS TO DIRECT LINE GENERAL TELEPHONE COMPANY,

A CORPORATION.

OF SAN FRANCISCO, CALIFORNIA,

DIRECT-LINE CIRCIJIT AND SWITCHING MECHANISM FOR TELEPHONE SYSTEMS.

SPECIFICATION forming part of Letters Patent No. 784,292, dated March 7, 1905.

Application filed November 21, 1903. Renewed July 11, 1904. Serial No. 216,053,

To n whom it may concern:

Be it known that we, ALBERT K. ANDEIANO, a citizen of the United States, residing in the city and county of San Francisco, State of California, and HERMANN HERBSTRI'IT, a-subject of the Emperor of Germany, residing in the city and county of New York, State of New York, have invented new and useful Improvements in Direct-Line Circuits and Switching Mechanism for Telephone Systems, of which the following is a specification.

The present improvements in telephone systems have for their object chiefly to provide a separate metallic circuit for each and all of the stations in a system, and especially to enable a considerable number of telephones or stations to be interconnected by the use of a relatively small number of wires.

A further object of the invention is to provide a signaling-circuit through which a bell or signal at the station being called up for conversation will be operated from the calling-station to the exclusion of the bells or signals at the remaining stations in the system, thereby confining the signaling to the two connected stations at such time.

The following description explains at length the nature of these improvements and the manner in which we carry out the invention to attain the above-mentioned objects, reference being had therein to the accompanying drawings, forming part thereof.

Figures 1 and 2 of the drawings are diagrams representing one application of our invention, in which fifteen separate metallic circuits for connecting electrically that number of stations in a system are obtained by the use of six conductors, the ringing-circuit being composed of two additional conductors and a separate battery therefor. In the diagram Fig. 1 station No. 1 is connected through its switching devices with station N o. 8 for signaling and talking, and in diagram Fig. 2 station No. 12 of the system is connected with station No. 15. The local circuits, the switching devices, and the ringingkey provided at every station are lndlcated in the diagram, and also the ringing-battery and its circuit common to all the stations. Fig. 3 is a diagram illustrating the manner in which by varying combinations of the conductors fifteen separate metallic circuits are obtained with six conductors. Fig. 4 is a front elevation of a station outfit, comprising a transmitter and a receiver, a ringing-key, and the circuitcontrolling means through which the local circuitis closed on the line by the act of taking down the receiver for use and is opened when the receiver is hung up, the transmitter being omitted. The line-' selecting devices or switches through which the local circuit is connected in the metallic circuit formed by the two selected lines are also shown. of the movable contacts of the two switches.

In the following description the terms direct conductor and return-conductor are used arbitrarily to designate the two sides of the metallic circuit that is formed by connecting two of the lines together; but it will be understood that the lines primarily used as direct conductors in one set, group, or number of the circuits illustrated in the diagrams may be simultaneously used as return-conductors for other circuits.

In applying the invention to interconnecting systems in which a central station is dispensed with each station is provided with switching devices through which a metallic circuit is completed between the station and any selected one of the remaining stations. A switching device controlling the connection of the the stations local circuit with the direct conductors of the remaining stations contains a stationary contact or switch point a/ for the conductor of every station and a movable contact or point A, to which one side of the local circuit is permanently connected. A second switching device, composed of stationary switch-points band a movable point B, is provided for connecting the remaining side of the local circuit with the line which may be appropriated or arranged for the return-conductor of the particular circuit selected for use.

Fig. 5 is a detail sectional view The switch A is designated for purposes of description as the direct-line switch, and the switch B as the return-line switch. The movable contact in each switch is pivotally attached, the point A to the center post a and the point B to a similar post f, so as to be movable in an arc over the stationary points. A spiral spring 9 on the. post 6 acts to normally retain the movable point A on that one of the switch-points commonly called the home contact, which is the terminal of the conductor or line that goes to form direct sides of the circuit of the station, and by its reaction when the movable point is set away from the home contact to another switch point the spring operates to return the movable point to its own home contact as soon as released. The movable pointB is returned to its normal position in the same manner by a similar spring g A ratchet-wheel h on the poste and a similar wheel 2' on the post f, together with pivoted detents m n, are employed to lock the movable points and hold them against the recoil of the springs when they are moved 0d the home contacts. Provision is made also for throwing off the detents and so releasing the movable points by the act of hanging up the receiver P on the telephone hook or support G, thereby resetting the switches automatically whenever the receiver is returned to place. This is done by means of a trippingarm 17, attached to the pivot of the hook, so arranged between the arm G of the hook and the detents that the hook in moving downward will throw the detents away from the rim of the ratchet-wheels and then allow the detents to return to place after the movable points have come back to position.

The lines designated by thenumerals 1 2 3 in the diagrams are primarily used as direct conductors in the system therein illustrated, and a terminal for each line will be found in the direct-line switch of every station, while the other set of lines, 4 5 6, primarily used as return-conductors, have corresponding terminals in the return-line switch at each station. By utilizing each return-conductor in turn as a common return-line for the three direct lines 1 2 3 nine separate metallic circuits in all are obtained. This number of circuits can be increased,however, without adding to the number of line conductors simply by utilizing in succession two of the conductors in the same set as return-conductors for all thelines in that set-that is to say, by making line 1 the common return for lines 2 and '8, used as direct conductors, and also forming an additional circuit having-line 3 for the direct and line 2 for the return conductor. In the same manner three additional metallic circuits are obtained by the combination of lines 4, 5, and 6, in which line 4 forms a'return for lines 5 and 6, used in that case as direct conductors, and line 5, used as the return for line 6, will give an additional circuit, making six additional circuits by utilizing for return-conductors those lines in each set or .number whichare available forthat purpose, according to the plan illustrated by the diagram Fig. 3. The system is capable of further expansion by adding one .or more conductors to either side, and it is susceptible of still greater extension by increasing the number of lines or conductors in both sets of conductors. For example, a set of ten direct conductors, with an equal number of return-conductors, will give, by means of the same combinations as carried out in the case of three conductors in each set, as already described, a capacity of one hundred and ninety complete metallic circuits for that number of stations.

The points a in the direct-line switch are numbered on the dial to agree with the switchnumbers of the stations that are individual to the lines, and the points 6 are similarly n'umbered to identify the return-line of the stations, so that the proper return-line to be used with the direct line of the station which is to be called up is selected by setting the movable switch-point B on the number that corresponds to the number of the direct-line contacts to which the switch-point A is set.

Figs. 1 and 2 illustrate an arrangement of the local circuit and the transmitting and receiving instruments at every station in which one side of the primary winding of the induction-coil H is connected to the movable point A of the direct-line switch and its other side to the switching-point B of the return-line switch by the connections .9 t, in which .9 indicates the frame and t a wire. In the lastmentioned connection is interposed the movable stop 20 of the ringing-key through which the ringing-battery K is thrown into the circuit when the ringing-key is pressed after the switches are set. The battery L of the local circuit is placed on the direct line outside the switch instead of between the induction-coil and the switch, where it is usually situated. The transmitter T is placed between the induction-coil H and the switch-point A and the receiver P is connected in a closed circuit with the secondary of the induction-coil. A lead 22 from one side of the ringing-battery K is connected to the back stop 20, and a similar connection 23 is carried from the other side of that battery to the stop 21. The wire 2? from one side of the primary of the induction-coil terminates at the stationary front stop 2 k, and the movable stop w is permanently connected to the return-line switchpoint B by the Wire 25. The movable stop 21 is situated in front of a third stationary stop 26, from which a wire 27 leads to the movable point A of the switch, and through that part the circuit from the ringing-battery is completed to the direct line on which the switch-pointAmay be set. The movable stop 21. is insulated from the stop w in front of it, as seen at 40.

That part'or feature of the invention which has for its object to provide a separate ringing-circuit between any two stations properly connected for talking consists in making the direct and the return conductors of the talkingcircuit parts of the ringing-circuit through which the signal at the station being called up will be operated from the opposite station on the circuit without disturbing the conditions or afl'ecting the operation of the instruments in the stations on any other circuits that may be in use at the same time. In carrying out the same one side of the bell M is permanently connected at the individual returnwire at the station, as indicated at 28, and the other side is similarly connected by a lead 29 to the direct-line conductor individual to the station. This connection is made outside the home contact a of the station and also beyond or outside of the local battery L when the same is situated outside the switch, as shown in the diagrams. A circuit-closer composed of contact-stops 30 31, placed in the connection 29 just under the arm of the hook, holds the same closed while the receiver remains on the hook-and opens the bell-circuit at that point whenever the receiver is removed, thus cutting out the bell when the receiver is taken down for use. The result of this arrangement is to connect the bell directly in the circuit formed of the direct and the return conductor on which the switch-points of the station are normally resting when the line is clear. The station is then ready to be called up, and the bell will be rung as soon as aeurrcnt from the common ringing-battery is passed over the conductors by pressing the ringing-key at the calling-station.

The operation of completing a circuit for ringing up and talking between one station and another will be understood from the diagram Fig. 1, where the subscriber at station No. 1 is represented as switching to and ringing up station No. 8, the intermediate stations between No. 3 and No. 8 being omitted on account of the limitations of the sheet. The switch-points A and B being properly moved oti' their home contacts and set on the switch-points in the direct-line and the returnline switches, which are the terminals of the lines belonging to station No. 8, the sub-- scriber at station No. 1 on pressing his ringing-key will close one side of the common ringing-battery K to the return-conductor of the circuit through the wire 22, the back stop 20, the front stop w, and the wire 25, connecting that stop to the switch-point B. The circuit is traced then through the connections last described and out over the lines 6 and 28 to the bell at station No. 8, and thence through the connection 29 to the direct line 2 and back to the calling-station, where the line terminates at the point 8, on which the switch-point A is resting. Through that member the circuit is continued through the switch A and to the two stops 26 21, that are brought together when the ringing-key is pressed, and thus at the same instant that the connection with one side of the ringing-battery is closed at the stops w and 20 the circuit to the opposite side of the battery is closed at 21 26. This circuit is indicated by the dotted lines in Fig. 1. On receiving the signal the subscriber at station No. 8 cuts out the bell and closes his local circuit on the direct and return lines by removing the receiver from its hook. By that operation the local circuit is closed at the contacts 32- 33 and the bell-circuit is opened at 30 31. The circuit for talking completed between the two stations is indicated by heavy lines in Fig. 1 and is readilytraced from one side of the transmitter at station No. l to the frame indicated at s to the direct-line switch A and outover line 2 to the opposite station and thence through the battery L, which is on that line, and through the movable point A of the direct-line switch of that station to the transmitter. Thence the circuit continues through the primary of the induction-coil to the front stop of the ringing-key and through the movable stop 00 and the connection 25 to the movable member B of the return-line switch of the station being called, whence it continues out over the return-line 6 to station No. 1, where it is traced in the same manner through the ringing-key 00, which will be resting against the front stop 2e after the ringing is done, and, finally, the circuit is carried from the front stop 24 and wire 25 and through the primary ot' the inductioncoil to the remaining side of the transmitter at the calling-station. The receivers are in closed circuits with the secondaries of the inductioncoils, and the battery on the line of the called station is brought into service, as already explained. Should the switch-points at station No. 8 be standing off their home contacts, it will be evident that the circuit cannot be completed between the two stations.

Diagram Fig. 2 represents the local circuits, switches, and connections of the last tourstations in the system containing lifteenstations and illustrates the metallic circuit completed for talking between station No. 12 and station No. 15, in which two of the lines primarily used as return-conductors are utilized for the circuit. Line 6 being employed for the direct line of station No. 15, it will be noticed that it is connected to the home contact a in the direct-line switch A; but as the sameline6 is also the common return for stations Nos. 10 and 11, the same wire 6 leads to one of the switch-points [10f the return-line switch B. Both conductors that go to form the circuit for station No. 15 are thus taken from the same set and are provided with proper terminals in both sets of switch-points at every station. The home contacts at every station are those stationary points on which the movable switch-points come to rest at the stop-pins 35 IIO as they are thrown back by the spiral springs. In every station but the first one the home contact has an additional point connected by a leg 37 to the wire leading to that one of the stationary points in the switch which corresponds to the switch-number of the station.

The advantages of this invention will be seen in its application to a system containing a number of direct and return conductors and in the increase in the number of metallic circuits that it is possible to produce by the addition of one or more conductors either to those primarily used for direct conductors or those used for return-conductors or by the addition of one or more conductors to both sets. For greater clearness of description the direct and return conductors are separately drawn in the diagrams; but in practice all the conductors are brought together in asingle cable and the interconnecting will be done inside the instrument at each station.

It will be observed that the stations included in a system such as we have described are arranged in groups, and while this grouping may be entirely arbitrary in the first instance the followingcharacteristics will be found incident to the arrangement, whatever it may be, namely: Witheach station is connected a number of direct-line wires leading to other stations and common to the stations of a group or groups and connected with the stationary points of the switching devices, and also a number of return-wires, each common to the stations of a group, these return-wires leading to the stationary points of switching devices. By means of the switching devices the said wires may be connected in varying combinations to form full metallic circuits, each circuit-consisting of two conductors, a direct and a return, and either of which may also be simultaneously employed as a member of another metallic circuit. By varying combinations we mean thata given conductor may be selected as a direct conductor and connected with one or another selected conductor of the system to be used as a return, thus establishing a full metallic circuit between the stations connected by such conductors and their switching devices. This is in contradistinction to those systems wherein it has been suggested to employ a plurality of pairs of conductors arranged to be connected with the local circuits of the different stations in the system, but wherein certain definite pairs of conductors are always used together, one of the conductors always serving as a return and the other as a direct, and wherein this relation of the two wires of the pair to each other is never interfered withthat is to say, one wire of one pair cannot be connected with a wire of another pair.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. In a telephone system, interconnecting conductors, consisting of a plurality of direct conductors, a plurality of return-conductors, and selecting devices for connecting the direct conductors and return-conductors in varying combinations to form separate circuits each composed of a direct conductor and a returnconductor.

2. In a telephone system, interconnecting conductors comprising a plurality of direct conductors, a plurality of return-conductors, and selecting means for connecting said conductors in varying combinations to form separate circuits, eachcircuit havingadirect conductor and a return-conductor individual to itself, said selecting means being adapted to utilize a direct conductor for the return-conductor of a circuit, and a return-conductor for the direct conductor of a circuit.

3. A system of conductors for the transmission of electricity between stations, comprising a series of wires arranged between the stations and means for selecting any one wire for use as a direct conductor of a circuit, and any other wire for use as a return-conductor, each circuit so completed for use being individual to a particular station in the system, substantially as set forth.

4. A system of conductors for the transmission of electricity, comprising a'series of Wires arranged between stations, adjustable means for selecting one Wire as a direct conductor, and other adjustable means for selectinganother wire as a return-conductor, to thus complete a circuit between stations, substantially as set forth.

5. Asystem of conductors for the transmission of electricity, comprising a series of conductors primarily used as direct conductors, and a separate series ofconductors primarily used as return-conductors, to form by varying combinations a plurality of'electrical circuits, and selecting means whereby any and all of the conductors in one seriesmay be used as a return-conductor to any and all of the conductors in the other series, and means for utilizing a conductor in the same series for the returnconductor of a circuit having one of the remaining conductors in the same series for its direct conductor.

'6. In a telephone system, stations divided into groups, a switching device at each station including stationary line-contacts corresponding in number to the stations in a group, and a movable contact adapted to connect the local circuit of the station with the line of another selected station, a series of direct-line wires to which the line-contacts of all the stations are connected, a separate returnwire to each group of stations and having terminals at every station, and means at every station controlling the connection between the local circuit of the station and any selected one of the return-wires.

7. In a telephone system, the combination with stations divided into groups, of a local cir- IIO cuit at every station in a group; a switching device including stationary contacts and a movable contact to which one side of the local circuit is connected, a series of direct-line wires corresponding in number to the stationary contacts in the switching device of the stations comprising a group, a separate returnwire common to the stations contained in the same group, and a switching device at every station including a stationary contact to each return-wire and a movable contact to which is connected the remaining side of the local circuit.

8. In a telephone system, stations arranged in separate groups having local circuits including a battery and an induction-coil, a set of direct-line wires common to all the stations and a series of return-wires to which the stations are connected in separate groups, each return-wire constituting a common return for the circuits of the stations in the same group, in combination with a switching device at each station adapted to connect one side of the local circuit of the station with the directline wire, a second switching device operating to connect the remaining side of said circuit with the opposite station over the common return-ire of that station, and means for calling one station from the other, comprising a battery, an electrically-operated signal device and circuit-closing means adapted to connect the signaling device at the called station with one side of the battery through the direct-line wire and with the remainingside of the battery over the common return to the exclusion of the signaling-circuits at all the remaining stations in the group.

9. In a telephone system, stations arranged in groups, a set of direct-line wires common to all the stations, a return-wire to each group constitutinga common return between one station and another selected station in the same group, switching-terminals for the direct-line wires and the common return-wires at each station, a separate switching device to the said terminals of each series adapted to connect the local circuit of the station with a selected direct-line wire and with selected common return-wire, an electrically-actuated signal device at each station, a common battery and circuit-closing means adapted to connect the signaling device with one side of the said battery over the direct line atthe selected station and with the other side of the battery over the connnon return-line.

10. In a telephone system circuits connecting a plurality of stations arranged in groups, comprising a set of direct-line wires common to all the stations in the group, a switching device at each station including terminals of the direct-line wires, and a movable contact operating to connect the local circuit of the station with a selected line-wire leading to another station, a separate return-wire common to the stations contained in the same group, a switching device adapted to complete the circuit over the common-return wire between one station and another, and a signaling device including an electrical]y-actuated signal at each station, a battery, and circuitclosing devices at the signaling-station operating to close one side of the battery on the signal at the selected station through the direct line, and the remaining side of the battery over the return-line.

11. In a telephone system, a common signal-circuit having terminals at each station, a series of independent line-wires between the stations terminating in separate contacts at each station, switches at the stations arranged to engage the said contacts of the line-wires, circuit-closing devices connected with said switches and arranged to make contact with the terminals of one of the leads of the signal-circuit, a common return-wire for the stations, signal devices connected with the return-wire, lines extending from the signal devices and terminating in contacts with which the circuit-closing devices normally engage, and branch lines at the stations normally leading from the common return-wire to terminals, the circuit-closing devices being arranged to connect the terminals of the other lead of the signal circuit with the contacts when moved to engaged the terminals of the lirstnamed lead, substantially as set forth.

12. A telephone system having the stations arranged in groups, return-wires common to each group of stations and extending to a contact at each station, line-wires corresponding in number to the stations in a group and terminating at each station in separate contacts, signal devices at each station, each connected on one side with the return-wire of the group to which it belongs, and on the other side'connected with the line-wire of its particular station, means for connecting any station with the line of any desired station of the system, comprising independent switches arranged to engage respectively with the contacts of the line-wires and of the return-wires, a signalcircuit, and means at each station for closing the signal-circuit through the signal of the selected station when the switches at the calling-station are properly set, substantially as set forth.

13. In a telephone system havinga plurality ofstations arranged in groups, the connectingcircuits comprising a plurality of line-wires terminating in contact-points at the several stations, and a return-wire common to the several stations of a group, a signal at each station, each permanently connected with the return-wire, a local circuit at each station arranged to be connected at one end with the return-wire and at its opposite end with any selected one of the contacts of the line-wires, a normally open signal-circuit having terminals at each station, and a circuit-closing device arranged to normally serve as a link in the of and arranged to be moved into engagement With any selected one of the contacts of the line-Wires, and another switch B at each station connected with the other lead of the local circuit and arranged to engage with any selected one of the terminals of the return-Wires, substantially as set forth.

ALBERT K. ANDRIANO. HERMANN HERBSTRITT.

Witnesses:

GEO. C. BURBANK, LEILA SHEARS ANDRIANO. 

